Papermakers fabrics

ABSTRACT

This invention relates to paper machine clothing, and more particularly to a woven forming medium, the machine direction yarns of which have crimps which undulate in the cross-machine direction, and to a method for producing same.

United States Patent 1191 Lefkowitz 1 1 Jan. 7, 1975 1 PAPERMAKERSFABRICS 3,159,530 12/1964 Helller et a1 162/348 3,327,866 61967 P' 1 1'1[75] Inventor: Leonard R. Lefkowltz, Latham, 3,335,986 8/1967 6 NY3,421,230 1/1969 Ward 3,473,576 10/1969 Amneus [73] Asslgnee S d/Corporauon Rensselaer 3,477,477 11/1969 DOlTlifl 139/383 A 3,603,3549/1971 Lee Ctal ..139/383A [22] PM: 1973 FOREIGN PATENTS OR APPLICATIONS[21] Appl. No.: 416,226 47,384 12/1939 Netherlands 139/425 A Related U SApplication Data 53,926 2/1943 Netherlands 139/425 A [63] Continuationof Ser. No. 831,899, June 10, 1969, OTHER PUBLICATIONS abandoned Tappi,v61. 45, N6. 3, March 1962, Form Ex Forming Fabrics by Charles A. Lee,page 160A. [52] US. Cl 139/425 A, l62/DIG. 1, 245/8 [51] Int. C1..D03d15/00, D03d 15/02, BOld 39/10 [58] Field Of searc 139 425 A, 425 R, 383A, g l ifi ifi g l Rhines; Robert 139/420 R, 245/8, 2, 162/348, 352,DIG. 1 Hargest [56] References Cited UNITED sTATEs PATENTS ABSTRACT 1927 498 9/1933 Lindsa at al l39/425 A Thls invention relates to papermachme clothmg, and 2755047 7/1956 Henkey 245/8 more particularly to awoven forming medium, the 2903021 9/1959 Raiderididi/IIIIII.I: 1391/3133A machine direction Y of which have CrhhlhS which 11;. 91 .99 W315i..13V97/74 25A undulate in the cross-machine direction, and to 83,032,441 5/1962 Beaumont et a1 139 425 A method for producing same.3,139,119 6/1964 Buchanan 139/425 A 11 Cl 6 D 3,143,150 8/1964 Buchanan139/425 A awmg gums BACKGROUND OF THE INVENTION In the typicalfourdrinier papermaking machine, an aqueous suspension of fibers, calledthe furnish is flowed onto a traveling fourdrinier wire or hydrofoils,medium, generally a woven belt of wire and/or synthetic material, toform a continuous sheet of paper or paper-like material. In thisconnection, the expression paper or paper-like material is used in abroad or generic sense and is intended to include such items as paper,kraft, board, pulp, asbestos sheet and other similar sheet-likestructures. As the furnish travels along on the fourdrinier wire, muchof its water content is removed by draining and a somewhatself-supporting continuous web is formed. This water removal is enhancedby the use of such well-known devices as hydrolfoils, table rolls,and/or suction boxes.

After leaving the forming section at the couch roll, the somewhatself-supporting web is transferred to a press section in the machinewhere still more of its water content is removed by passing it through aseries of pressure nips formed by cooperating press rolls,

these press rolls also serving to compact the web as well. The paper webis then transferred to a dryer section in the machine where it is passedabout and held in heat transfer relationshipv with a series of heated,cylindrical rolls by which still further amounts of water are removed byevaporation. Finally, the paper web is passed through a series ofcalender rolls where loose fiber ends are laid down and the paper web isprovided with a smooth finish, after which the paper web is collected ona suitable reel.

The present invention relates to forming media. A forming medium isdesigned to be (1) fluid permeable so that large amounts of water may bedrained therethrough from the deposited furnish, and yet not so open asto permit large numbers of deposited fibers to pass therethrough andthus interfere with the formation of the paper web, produce a sheet ofpoorer printing quality and result in a high loss of constituent fibersin the form of white water, (2) flexible in order to avoid prematurefailure thereof due to fatigue, (3) smooth and uniform in order toprevent marking or undue marring of the paper surface, (4) dimensionallystable in order to prevent shoving" or dimensional changes which canvary the permeability of the medium, and therefore its drainage andother characteristics as well as the characteristics of the paper formedthereon from place to place, and (5) resistant to wear and corrosion inthe aqueous environment of the forming section.

Forming media conventionally have been woven wire structures made frommaterials such as phosphor bronze, bronze, stainless steel, brass orsuitable combinations thereof. Such forming wires are woven flat in aplain, twill, satin or other suitable weave pattern. Subsequent to theweaving of the wire, both ends thereof are joined to form an endlessbelt-like structure as by welding the two ends of the wire together.Recent developments in the papermaking field have shown that fabrics ofsuperior suitability for use as forming medium may be woven entirely orin part of synthetic materials. Nylon, a polyamide fiber, has been foundto be suitable. Other examples of suitable materials are polyesters,such as Dacron, or acrylic fibers such as Orlon, dynel and Acrilan orcopolymers, such as saran. The warp and weft yarns may be of the same ordifferent constituent materials and/or constructions, and may be in theform of monofilament or multifilament yarns, or they may be yarns madeup of suitable strands or plies which are in turn formed from staplefiber. Such fabrics may be woven flat and made endless by, for example,hand weaving the two ends of the fabric together, or they may be wovenendless, as, for example, the fabric described and claim in U.S. Pat.No. 2,903,021, Holden et al.

Heretofore, fabric manufacturers have subjected fabrics produced fromsynthetic materials to special treatment(s) subsequent to the weavingthereof in order to obtain a product having the desired physicalcharacteristics. These treatments are time-consuming and involve the useof expensive equipment. For example, and referring to FIGS. 1, 2 and 3,in the case of such a forming fabric 2 which has been woven flat andsubsequently joined, the warp yarns 4 have crimps therein, hereinreferred to as vertical crimps, which undulate in a plane normal to thepaper contacting surface of the fabric. These vertical crimps are theresult, in part, of the warp yarns 4 bending over and under the weft orfilling yarns 6 during the weaving of the fabric 2. When the fabric 2 ispositioned on the papermaking machine, the warp yarns 4 extend in thedirection of the path of travel of the fabric, which path direction isreferred to herein as the machine" direction. Accordingly, when thefabric 2 is in operation and subjected to machine direction tensions ashigh as pounds per lineal inch of width, (referred to in FIG. 2 byarrows T-T) there is a tendency for the warp yarns 4 to straighten out;that is, the vertical crimp in the machine direction is reduced as aresult of the high machine direction tensions. In addition, thestraightening out of the machine direction yarns causes crimpinterchange;" that is, by reducing the vertical crimp in the machinedirection yarns the vertical crimp in the cross-machine-direction isincreased. The net effect is that during the useful life of the fabricit elongates in the machine direction, and

becomes narrower in the cross-machine direction, to such an extent thatit must be removed from the paper machine. The fabric manufacturer facesa dilemma, however, in that although he could substantially reduce thevertical crimp in the machine direction yarns and thereby reduce thetendency of the fabric to elongate in the machine direction during thepapermaking operation by (a) producing a fabric which is undersize; thatis, the circumferential length of which is less than that which isrequired in order for the fabric to properly fit on the paper-makingmachine, and (b) prior to positioning the fabric on the paper machine,stretching the fabric in the machine direction until it reaches therequired length, since the fabric has been woven flat, it is desirableto maintain the vertical crimp in the machine direction yams in order toprevent the fabric from rupturing in the seam area. For example,Schuster, U.S. Pat. No. 3,238,594 discloses a forming medium which hasbeen woven flat and subsequently joined, the join being dependent, inpart, upon the vertical crimp in the machine direction yarns. Thetendency of the fabric seam to rupture is reduced as a result of theinterlocking in the seam area of the machine direction yarns with thoseyarns which extend in a direction substantially at right angles to themachine direction yarns, herein referred to as cross-machine directionyarns. Such interlocking is dependent, in part, upon the vertical crimpin the machine direction yarns. Fabric manufacturers have coped with thedilemma of producing a fabric which has been woven flat and subsequentlyjoined, which has a high degree of elongation resistance and yet enoughvertical crimp in the machine direction yarns to reduce the tendency forthe seam or join to rupture, by subjecting the fabric to variousstabilization treatments. An example of a resin treatment suitable foruse on papermakers forming fabrics is that set forth in US Pat. No.3,032,441, Beaumont et al.

At least one fabric manufacturer has attempted to cope with this dilemmaby endless weaving forming fabrics from synthetic materials. Since thefabric is woven endless there is no seam, and therefore any verticalcrimp in the machine direction yarns can be substantially eliminated sothat fabric elongation in the machine direction will be substantiallyreduced during operation on the paper machine. Forming fabrics whichhave been woven endless, however, must also be subjected to subsequentstabilization treatments. Since there is very little, if any, verticalcrimp in the machine direction yarns and since these yarns aresubstantially parallel to each other, there will be a tendency for thecross-machine direction yarns, which yarns pass over and under themachine direction yarns in a sequence depending upon the weave pattern,to move or slide relative to each other and the machine direction yarns,thereby varying the dimensions of the rectangular interstices in thefabric. This shoving of the crossmachine direction yarns can besubstantially reduced by subjecting the fabric to a stabilizationtreatment, as, for example, that treatment described and claimed in theBeaumont et al patent referred to above.

Accordingly, it is an object of this invention to produce a formingmedium which will not elongate significantly in the machine directionwhen operating on a paper machine.

Another object of this invention is to produce a forming medium whichdoes not narrow significantly in the cross-machine direction whenoperating on a paper machine.

Still another object of this invention is to produce a forming medium,the cross-machine direction yarns of which donot move significantlyrelative to each other or to the machine direction yarns.

A further object of this invention is to produce a forming fabrich whichis dimensionally stable in both the machine and cross-machine directionswithout the necessity of subjecting the fabric to further stabilizationtreatment.

Still a further object of this invention is to produce a forming fabric,the permeability of which does not significantly vary during the life ofthe fabric.

SUMMARY OF THE INVENTION This invention achieves these and other objectsby means of a forming medium comprising a crowded weave havinginterwoven substantially nondeformable warp and weft yarns in which theaxes of the machine direction yarns reside substantially in the samelongitudinal plane and have crimps therein which undulate in thecross-machine direction.

DESCRIPTION OF DRAWINGS This invention may be cearly understood byreference to the attached drawings in which:

FIG. 1 is a fragmentary plan view of a forming fabric embodying theprior art;

FIG. 2 is a sectional view along the line 2-2 in FIG.

FIG. 3 is a sectional view along the line 33 in FIG.

FIG. 4 is a fragmentary plan view of a forming fabric embodying theteachings of the present invention;

FIG. 5 is a sectional view along the line 5-5 in FIG. 4; and

FIG. 6 is a sectional view along the line 66 in FIG. 4.

DESCRIPTION OF PREFERRED EMBODIMENT The embodiment of this invention,which is illustrated in FIGS. 4, 5 and 6, is one which is particularlysuited for achieving the objects of this invention. FIG. 4 depicts asingle layered fourdrinier fabric 12 which comprises yarns Woven endlessso that the warp yarns 14 extend in the crossmachine direction and thefilling yarns 16 extend in the machine direction. A suitable materialfor these yarns is 8 mil monofilament synthetic polyester. It should benoted that forming fabric 12 may be a multilayered fabric, as, forexample, that which is disclosed in Justus et al, US. Pat. No.3,l27,308,in which case the teachings of this invention are applicableto each layer thereof. It should be further noted that the scope of thepresent invention is not limited to the polyester monofilament yarnsdescribed above. As explained in detail hereinafter any yarn, wire, orstrand-like material, herein referred to as yarn, having the requisitephysical characteristics for use as a constituent of a forming mediummay be used, providing such material is substantially nondeformable,and, in the case where a fabric embodying the present invention isproduced by shrinking the cross-machine direction yarns, as described,hereinafter, is susceptable to shrinking and maintaining its reducedlength. By nondeformable is meant that the yarns in the completed fabricare of such a nature that when the fabric is in use theircross-sectional dimensions will remain substantially the same underpressure applied thereto as a result of tension applied to the fabric.As will be seen, this characteristic is utilized to ensure that thediameter d of the cross-machine direction yarns will not be less thanthe average distance h measured in the cross-machine direction betweenadjacent machine direction yarns. For example, other types ofmonotilament yarns, such as polyamides, may be used. Most untreatedmultifilament yarns will not be suitable for the purposes of the presentinvention since, unless specially treated, such yarns are usuallydeformable. In certain instances, however, multifilament yarns may berendered substantially nondeformable, either prior or subsequent toweaving, as, for example, by impregnating them with resin. It should benoted that by the use of the word diameter it is not meant to limit thescope of the present invention to the use of yarns, a crosssectionalview of which is circular. Rather, diameter" is used in its broadersense and means the length of a straight line through the center ofgravity of a crosssectional view of a circular or noncircular yarn.

FIG. 4 depicts a fabric 12 which incorporates a fourharness satin weave.In one suitable such construction there are 84 picks per inch (machinedirection yarns) and 49 ends per inch (cross-machine direction yarns).While FIG. 4 depicts a four-harness satin weave, other types of weaves,for example, twill weaves, may be utilized. Referring to FIGS. 5 and 6,it can be seen that, for example, by endless weaving 8 mil polyestermonofilament yarns in a four-harness satin weave having 49 ends per inchand 84 picks per inch, a fabric 12 is produced wherein the axes of themachine direction yarns 16 lie substantially in the same longitudinalplane; that is, the vertical distance v between the axes of adjacentmachine direction yarns is less than the diameter d of the cross-machinedirection yarns. In addition, a weave pattern is effectuated, which isreferred to herein as a crowded weave, wherein the interrelationshipbetween the machine and cross-machine direction yarns is such that thediameter of some, and preferably all, of the cross-machine directionyarns 14 is greater than the average distance, measured in thecross-machine direction, separating the peripheral surfaces of adjacentmachine direction yarns 16. This will be the case, for example, when 8mil monofilaments are woven endless in a four-harness satin weave having62 to 95 picks per inch.

As depicted in FIG. 4, machine direction yarns 16 have crimps therein,herein referred to as lateral crimps, which undulate in thecross-machine direction in the longitudinal plane of the fabric; thatis, in viewing either surface of the fabric, the machine direction yarns16 undulate to the left and right. This undulation is such that the axesof adjacent machine direction yarns are furthest apart at those pointswhere a crossmachine direction yarn interlaces therebetween, as, forexample, where cross-machine direction yarn 14 interlaces from beneaththe fabric 12 and up between adjacent machine direction yarns 16, 16.Similarly, the axes of adjacent machine direction yarns are closesttogether at those points where there is no cross-machine direction yarntherebetween. Referring to FIG. 4, it can be seen that many of theinterstices in the fabric have a trapezoidal configuration as a resultof the lateral crimp in the machine direction yarns. As explained indetail hereinafter, these lateral crimps result from (I) the use ofyarns which are substantially nondeformable; (2) the maintaining of themachine direction yarns 16 in substantially the same longitudinal plane;and (3 the crowded weave pattern referred to above.

It has been found that a forming fabric embodying the teachings of thepresent invention exhibit unexpected results when placed upon apapermaking machine. For example, although there are lateral crimps inthe machine direction yarns, when the fabric is placed in operation on apapermaking machine and subjected to the high machine direction tensionsreferred to above, the lateral crimp is maintained, elongation of themachine direction yarns is negligible, and crimp interchange issubstantially reduced. Without wishing or intending to be bound by atheory of operation, and referring to FIG. 4, it is believed that thelateral crimp is not removed from the machine direction yarns 16 duringthe papermaking operation because of at least two interrelated factors.Since all of the machine direction yarns 16 lie in substantially thesame plane, when tension is applied to the fabric in the machinedirection (depicted by arrows T'-T'), any tendency which the machinedirection yarns 16 might have to straighten out would be exhibited bycrossmachine direction movement, in that plane, of the machine directionyarns. Such lateral movement will cause machine direction yarns 16 toexert a force (denoted by arrows F-F) against an adjacent crossmachinedirection yarn 14 in an attempt to straighten out. However, since all ofthe yarns are substantially nondeformable, the cross-machine directionyarns 14 will offer an opposing force which is equal in magnitude(depicted by arrows FF'), thereby preventing the removal of the lateralcrimp in the machine direction yarns 16.

Another unexpected result is that since the lateral crimp is maintainedin the machine direction yarns 16, the cross-machine direction yarns 14do not move with reference to each other or the machine direction yarns.It is believed that this is the result of the interlocking of thelaterally crimped machine direction yarns 16 with the vertically crimpedcross-machine direction yarns 14. In addition, however, there will be atendency for the cross-machine direction yarns 14 to resist machinedirection movement along and in the interstices of the fabric 12 becauseof the trapezoidal configuration of the interstices; that is, there willbe little tendency for the cross-machine direction yarns 14 to slideinto the wedge-shaped end of the fabric opening 18.

The dimensional stability achieved by this invention has the addedadvantage of being obtained without the necessity for subjecting thefabric to a subsequent resin-impregnated heat stabilization or othertreatment although, of course, such treatments might be employed ifdesired.

The process of the invention comprises weaving a fabric fromnondeformable yarns in such a manner that the machine direction yarnslie substantially in the same plane, as will be the case, for example,when such a fabric is woven endless, and such that a crowded weave isperfected. The specific pattern chosen must be such that a cross-machinedirection yarn does not interlace between two adjacent machine directionyarns at a point where such cross-machine direction yarn will interferewith the effectuation of a lateral crimp in the machine direction yarn.For example, and referring to FIG. 4, cross-machine direction yarn 14should not interlace between machine direction yarns 16 at point A,because to do so would interface with the lateral movement of yarn 16,as indicated by arrow L, which would prevent yarn 16 from obtaining alateral crimp at that point. As a practical matter, what this means isthat any weave pattern may be used other than a plain weave.

The crowded weave may be perfected during the weaving of the fabric orsubsequent thereto. If done during the weaving of the fabric, the pickcount; that is, the number of machine direction yarns per inch in afabric which is woven endless, will have to be such that, as notedabove, the cross-machine direction spacing between adjacent machinedirection yarns is less than the diameter of at least some of the warpor crossmachine direction yarns. The following table lists four fabricexamples, each of which comprises 8 mil polyester monofilament yarnswhich have been woven endless in a four-harness satin weave, the yarncount being such that a crowded weave has been perfected:

TABLE No. 1

Fabric Number 1 2 3 4 Ends per inch (Cross-Machine Direction) 45 5O 5560 Picks per inch (Machine Direction) 79 74 66 64 Average Hole Dimension(mils) (Cross-Machine Direction) 4.7 5.1 7.3 7.8

In the alternative, the crowded weave may be perfected subsequent to theweaving of the fabric. This may be accomplished by weaving the fabricsuch that the diameter of the cross-machine direction yarns is equal toor less than the average distance measured in the cross-machinedirection between the peripheral surface of adjacent machine directionyarns, and subsequently reducing the length of the cross-machinedirection yarns by shrinking same. For example, the length of thecross-machine direction yarns can be reduced by applying machinedirection tension to the fabric while subjecting it to heat. In such acase, the amount of pressure and degree of heat will vary depending uponthe results desired. in this manner, the cross-machine direction yarnswill shrink in length, thereby pulling the machine direction yarnscloser together. The heating of the fabric should be continued until acrowded weave is perfected. Table No. 2 refers to the same four fabricexamples listed in Table No. 1 subsequent to subjecting each of them toheat stabilization. The fabrics listed in Table No. 2 were subjected toa maximum machine direction tension of about 95 pounds per lineal inchof width for about 2 hours, and to a maximum temperature of about 400 F.

A single layered forming fabric embodying the teachings of the presentinvention was woven endless using 8 mil monofilament synthetic polyesteryarns. The fabric was woven into a four-harness satin weave having 70picks per inch (machine direction yarns) and 50 ends per inch(cross-machine direction yarns), the distance between the peripheralsurfaces of adjacent machine direction yarns measuring 6.4 mils. Inorder to perfect an even tighter weave, the fabric was subjected toabout 50 pounds per lineal inch tension in the machine direction andheated to a temperature of about 400 F. for about 4 minutes. Thefinished product had 80 picks per inch and 49 ends per inch, the averagedistance measured in the cross-machine direction between the peripheralsurfaces of adjacent machine direction yarns thereby being reduced to4.5 mils. The fabric was subsequently positioned on a fourdrinier machine in the manufacture of fine paper. It was observed that fabricstretch in the machine direction and shoving of the cross-machinedirection yarns was substantially eliminated, and the quality of thepaper produced was not reduced, notwithstanding that the fabric was inoperation for a period of 320 days. Theretofore, the average life ofsynthetic forming fabrics on the same machine was about 73 days.

EXAMPLE 2 A forming fabric was manufactured as set forth in Example 1except that subsequent to subjecting the fabric to heat there were 82picks per inch, and the average distance measured in the cross-machinedirection yarns between the peripheral surfaces of adjacent machinedirection yarns was reduced accordingly from 6.4 mils to 4.2 mils. Thisfabric was also positioned on a fourdrinier machine in the manufactureof fine paper. As in the case of the fabric referred to in Example 1,fabric stretch in the machine direction and shoving of the cross-machinedirection yarns was observed to be substantially reduced, and thequality of the paper produced was not reduced.

EXAMPLE 3 Another forming fabric was manufactured as set forth inExample 1, except that subsequent to the weaving of the fabric therewere 65 picks per inch, the average distance measured in the machinedirection between the peripheral surfaces of machine direction yarnsbeing 7.5 mils. This fabric was also subjected to the same heattreatment as referred to in Example 1, subsequent to which there were 75picks per inch, the average distance between adjacent machine directionyarns being reduced to 5.3 mils. This fabric has been running on apapermaking machine which produces fine paper for 65 days and is stillrunning with results similar to these noted in Example 1 and 2.

The embodiments which have been described herein are but some of severalwhich utilize this invention and are set forth here by way ofillustration but not of limitation. It is apparent that many otherembodiments which will be readily apparent to those skilled in the artmay be made without departing materially from the spirit and scope ofthis invention.

I claim:

1. A forming belt for a papermaking machine comprising:

a. nondeformable warp and weft yarns interwoven to form said belt withcertain of said yarns extending in the lengthwise direction of said beltand other yarns extending in the widthwise direction of said belt, saidwidthwise yarns being woven such that they are not interlaced betweentwo adjacent lengthwise yarns at a point where said widthwise yarns willinterfere with lateral crimping in said lengthwise yarns;

b. the vertical distance between the axes of adjacent lengthwise yarnsbeing less than the diameter of said widthwise yarns to substantiallyreduce vertical crimp in said lengthwise yarns; and,

c. said widthwise yarns having a diameter, measured at a point wheresaid widthwise yarns contact adjacent lengthwise yarns, which is greaterthan the arithmetical mean displacement between adjacent surfaces ofsaid lengthwise yarns, the' lateral dis tance between adjacentlengthwise yarns varying substantially continuously along the length ofthe fabric to accommodate the interlacing of said b. the verticaldistance between the axes of adjacent widthwise yarns. lengthwise yarnsbeing less than the diameter of 2. A forming belt for a papermakingmachine comsaid widthwise yarns to substantially reduce vertiprising:cal crimp in said lengthwise yarns; and,

a. nondeformable synthetic monofilament warp and 5 c. said widthwiseyarns having a diameter, measured weft yarns interwoven to form saidbelt with certain of said yarns extending in the lengthwise direction ofsaid belt and other yarns extending in the widthwise direction of saidbelt, said widthwise yarns being woven such that they are not interlacedbetween two adjacent lengthwise yarns at a point where said widthwiseyarns will interfere with lateral crimping in said lengthwise yarns;

b. the vertical distance between the axes of adjacent lengthwise yarnsbeing less than the diameter of said widthwise yarns to substantiallyreduce vertical crimp in said lengthwise yarns; and,

. said widthwise yarns having a diameter, measured at a point where saidwidthwise yarns contact adjacent lengthwise yarns, which is greater thanthe arithmetical mean displacement between adjacent surfaces of saidlengthwise yarns, the lateral distance between adjacent lengthwise yarnsvarying substantially continuously along the length of the fabric toaccommodate the interlacing of said widthwise yarns.

at a point where said widthwise yarns contact adjacent lengthwise yarns,which is greater than the arithmetical mean displacement betweenadjacent surfaces of said lengthwise yarns, the lateral distance betweenadjacent lengthwise yarns varying substantially continuously along thelength of the fabric to accommodate the interlacing of said widthwiseyarns.

5. An endless woven forming belt for a papermaking machine comprising:

a. nondeformable warp and weft yarns interwoven to form said belt withweft yarns extending in the lengthwise direction of said belt and warpyarns extending in the widthwise direction of said belt, said warp yarnsbeing woven such that they are not interlaced between two adjacent weftyarns at a point where said warp yarns will interfere with lateralcrimping in said weft yarns,

b. the vertical distance between the axes of adjacent weft yarns beingless than the diameter of said warp yarns to substantially reducevertical crimp in said weft yarns; and, c. said warp yarns having adiameter, measured at a point where said warp yarns contact adjacentweft 3. A forming belt for a papermaking machine comprising:

a. nondeformable synthetic monofilament warp and weft yarns whichconsist substantially entirely of yarns, which is greater than thearithmetical mean one or more synthetic materials selected from thedisplacement between adjacent surfaces of said group consisting ofpolyamides, polyesters, acrylics weft yarns, the lateral distancebetween adjacent and copolymers interwoven to form said belt with weftyarns varying substantially continuously along certain of said yarnsextending in the lengthwise di- 3 the length of the fabric toaccommodate the interrection of said belt and other yarns extending inthe widthwise direction of said belt, said widthwise yarns being wovensuch that they are not interlaced between two adjacent lengthwise yarnsat a point where said widthwise yarns will interfere with latse}iiwidthwise yarns having a diameter, measuredat a pbm vvhere saidwidthwise yarns contacTadjacent lengthwise yarns, which is greater thanthe arithmetical mean displacement between adjacent surfaces of saidlengthwise yarns, the lateral distance between adjacent lengthwise yarnsvarying substantially continuously along the length of the fabric toaccommodate the interlacing of said widthwise yarns.

lacing of said warp yarns. 6. A forming belt for a papermaking machinecomprising:

a. nondeformable warp and weft yarns interwoven to form said belt withwarp yarns extending in the era] crimping in said lengthwise yarns,lengthwise direction of said belt and weft yarns exb. the verticaldistance between the axes of adjacent tending in the widthwise directionof said belts, said lengthwise yarns being less than the diameter ofweft yarns being woven such that they are not insaid widthwise yarns tosubstantially reduce vertiterlaced between two adjacent warp yarns at acal crimp in said lengthwise yarns; and, point where said weft yarnswill interfere with latwarp yarns, the lateral distance between adjacentwarp yarns varying substantially continuously along the length of thefabric to accommodate the 4. A forming belt for a papermaking machinecom prising:

a. nondeformable warp and weft yarns which consist substantiallyentirely of one or more synthetic materials selected from the groupconsisting of polyamides, polyesters, acrylics and copolymers interwovenin a four-harness sateen weave to form said belt with certain of saidyarns extending in the lengthwise direction of said belt and other yarnsextending in the widthwise direction of said belt, said widthwise yarnsbeing woven such that they are not interlaced between two adjacentlengthwise yarns at a point where said widthwise yarns will interferewith lateral crimping in said lengthwise yarns;

interlacing of said weft yarns. 7. An endless woven forming belt for apapermaking machine comprising:

a. nondeformable synthetic monofilament polyester warp and weft yarnsinterwoven in a four-harness sateen weave to form said belt with 62 toweft yarns per inch extending in the lengthwise direction of said beltand warp yarns extending in the widthwise direction of said belt, saidwarp yarns being woven such that they are not interlaced be tween twoadjacent weft yarns at a point where said warp yarns will interfere withlateral crimping in said weft yarns;

b. the vertical distance between the axes of adjacent weft yarns beingless than the diameter of said warp yarns to substantially reducevertical crimp in said weft yarns; and,

c. said warp yarns having a diameter, measured at a point where saidwarp yarns contact adjacent weft yarns, which is greater than thearithmetical mean displacement between adjacent surfaces of said weftyarns, the lateral distance between adjacent weft yarns varyingsubstantially continuously along the length of the fabric to accommodatethe interlacing of said warp yarns.

8. A method of producing a forming belt for a papermaking machine withcertain of said yarns extending in the lengthwise direction of said beltand other yarns extending in the widthwise direction of said beltcomprising the steps of weaving said belt from nondeformable warp andweft yarns with said widthwise yarns being woven such that they are notinterlaced between two adjacent lengthwise yarns at a point where saidwidthwise yarns will interfere with lateral crimping in said lengthwiseyarns, and with the vertical distance between the axes of adjacentlengthwise yarns being less than the diameter of said widthwise yarns tosubstantially reduce vertical crimp in said lengthwise yarns, and withthe arithmetical mean displacement between adjacent surfaces of saidlengthwise yarns being less than the diameter of said widthwise yarns,measured at a point where said widthwise yarns contact adjacentlengthwise yarns, the lateral distance between adjacent lengthwise yarnsvarying substantially continuously along the length of the fabric toaccommodate the interlacing of said widthwise yarns.

9. A method of producing a forming belt for a papermaking machine havingcertain of said yarns extending in the lengthwise direction of said beltand having other of said yarns extending in the widthwise direction ofsaid belt comprising the steps of weaving said belt from nondeformablewarp and weft yarns with said widthwise yarns being woven such that theyare not interlaced between two adjacent lengthwise yarns at a pointwhere said widthwise yarns will interfere with lateral crimping in saidlengthwise yarns, and with the vertical distance between the axes ofadjacent lengthwise yarns being less than the diameter of said widthwiseyarns to substantially reduce vertical crimp in said lengthwise yarns,and reducing the length of the widthwise yarns by shrinking said yarnsuntil the arithmetical mean displacement between adjacent surfaces ofsaid lengthwise yarns is less than the diameter of said widthwise yarns,measured at a point where said widthwise yarns contact adjacentlengthwise yarns, while holding said lengthwise yarns such that saidvertical distance remains less than said diameter, to allow the lateralbetween adjacent lengthwise yarns to vary substantially continuouslyalong the length of the fabric to accommodate the interlacing of saidwidthwise yarns.

10. A method of producing a forming belt for a papermaking machinehaving certain of said yarns extending in the lengthwise direction ofsaid belt and having other of said yarns extending in the widthwisedirection of said belt comprising the steps of weaving said belt fromnondeformable warp and weft yarns with said widthwise yarns being wovensuch that they are not interlaced between two adjacent lengthwise yarnsat a point where said widthwise yarns will interfere with lateralcrimping in said lengthwise yarns, and with the vertical distancebetween the axes of adjacent lengthwise yarns being less than thediameter of said widthwise yarns to substantially reduce vertical crimpin said lengthwise yarns, and reducing the length of the widthwise yarnsby subjecting said belt to lengthwise tension and heat until thearithmetical mean displacement between adjacent surfaces of saidlengthwise yarns is less than the diameter of said widthwise yarns,measured at a point where said widthwise yarns contact adjacentlengthwise yarns, while holding said lengthwise yarns such that saidvertical distance remains less than said diameter, to allow the lateraldistance between adjacent lengthwise yarns to vary substantiallycontinuously along the length of the fabric to accommodate theinterlacing of said widthwise yarns.

11. A method of producing an endless woven forming belt for apapermaking machine with weft yarns extending in the lengthwisedirection of said belt and warp yarns extending in the widthwisedirection of said belt comprising the steps of weaving said belt fromnondeformable yarns with said warp yarns being woven such that they arenot interlaced between two adjacent weft yarns at a point where saidwarp yarns will interfere with lateral crimping in said weft yarns, andwith the vertical distance between the axes of adjacent weft yarns beingless than the diameter of said warp yarns to substantially reducevertical crimp in said weft yarns, and with the arithmetical meandisplacement between adjacent surfaces of said weft yarns being lessthan the diameter of said warp yarns, measured at a point where saidwarp yarns contact adjacent weft yarns, the lateral distance betweenadjacent weft yarns varying substantially continuously along the lengthof the fabric to accommodate the interlacing of said warp yarns.

1. A forming belt for a papermaking machine comprising: a. nondeformablewarp and weft yarns interwoven to form said belt with certain of saidyarns extending in the lengthwise direction of said belt and other yarnsextending in the widthwise direction of said belt, said widthwise yarnsbeing woven such that they are not interlaced between two adjacentlengthwise yarns at a point where said widthwise yarns will interferewith lateral crimping in said lengthwise yarns; b. the vertical distancebetween the axes of adjacent lengthwise yarns being less Than thediameter of said widthwise yarns to substantially reduce vertical crimpin said lengthwise yarns; and, c. said widthwise yarns having adiameter, measured at a point where said widthwise yarns contactadjacent lengthwise yarns, which is greater than the arithmetical meandisplacement between adjacent surfaces of said lengthwise yarns, thelateral distance between adjacent lengthwise yarns varying substantiallycontinuously along the length of the fabric to accommodate theinterlacing of said widthwise yarns.
 2. A forming belt for a papermakingmachine comprising: a. nondeformable synthetic monofilament warp andweft yarns interwoven to form said belt with certain of said yarnsextending in the lengthwise direction of said belt and other yarnsextending in the widthwise direction of said belt, said widthwise yarnsbeing woven such that they are not interlaced between two adjacentlengthwise yarns at a point where said widthwise yarns will interferewith lateral crimping in said lengthwise yarns; b. the vertical distancebetween the axes of adjacent lengthwise yarns being less than thediameter of said widthwise yarns to substantially reduce vertical crimpin said lengthwise yarns; and, c. said widthwise yarns having adiameter, measured at a point where said widthwise yarns contactadjacent lengthwise yarns, which is greater than the arithmetical meandisplacement between adjacent surfaces of said lengthwise yarns, thelateral distance between adjacent lengthwise yarns varying substantiallycontinuously along the length of the fabric to accommodate theinterlacing of said widthwise yarns.
 3. A forming belt for a papermakingmachine comprising: a. nondeformable synthetic monofilament warp andweft yarns which consist substantially entirely of one or more syntheticmaterials selected from the group consisting of polyamides, polyesters,acrylics and copolymers interwoven to form said belt with certain ofsaid yarns extending in the lengthwise direction of said belt and otheryarns extending in the widthwise direction of said belt, said widthwiseyarns being woven such that they are not interlaced between two adjacentlengthwise yarns at a point where said widthwise yarns will interferewith lateral crimping in said lengthwise yarns, b. the vertical distancebetween the axes of adjacent lengthwise yarns being less than thediameter of said widthwise yarns to substantially reduce vertical crimpin said lengthwise yarns; and, c. said widthwise yarns having adiameter, measured at a point where said widthwise yarns contactadjacent lengthwise yarns, which is greater than the arithmetical meandisplacement between adjacent surfaces of said lengthwise yarns, thelateral distance between adjacent lengthwise yarns varying substantiallycontinuously along the length of the fabric to accommodate theinterlacing of said widthwise yarns.
 4. A forming belt for a papermakingmachine comprising: a. nondeformable warp and weft yarns which consistsubstantially entirely of one or more synthetic materials selected fromthe group consisting of polyamides, polyesters, acrylics and copolymersinterwoven in a four-harness sateen weave to form said belt with certainof said yarns extending in the lengthwise direction of said belt andother yarns extending in the widthwise direction of said belt, saidwidthwise yarns being woven such that they are not interlaced betweentwo adjacent lengthwise yarns at a point where said widthwise yarns willinterfere with lateral crimping in said lengthwise yarns; b. thevertical distance between the axes of adjacent lengthwise yarns beingless than the diameter of said widthwise yarns to substantially reducevertical crimp in said lengthwise yarns; and, c. said widthwise yarnshaving a diameter, measured at a point where said widthwise yarnscontact adjacent lengthwise yarns, which is greater than thearithmetical mean displacement between adjacent surfaces of saidlengthwise yarns, the lateral distaNce between adjacent lengthwise yarnsvarying substantially continuously along the length of the fabric toaccommodate the interlacing of said widthwise yarns.
 5. An endless wovenforming belt for a papermaking machine comprising: a. nondeformable warpand weft yarns interwoven to form said belt with weft yarns extending inthe lengthwise direction of said belt and warp yarns extending in thewidthwise direction of said belt, said warp yarns being woven such thatthey are not interlaced between two adjacent weft yarns at a point wheresaid warp yarns will interfere with lateral crimping in said weft yarns,b. the vertical distance between the axes of adjacent weft yarns beingless than the diameter of said warp yarns to substantially reducevertical crimp in said weft yarns; and, c. said warp yarns having adiameter, measured at a point where said warp yarns contact adjacentweft yarns, which is greater than the arithmetical mean displacementbetween adjacent surfaces of said weft yarns, the lateral distancebetween adjacent weft yarns varying substantially continuously along thelength of the fabric to accommodate the interlacing of said warp yarns.6. A forming belt for a papermaking machine comprising: a. nondeformablewarp and weft yarns interwoven to form said belt with warp yarnsextending in the lengthwise direction of said belt and weft yarnsextending in the widthwise direction of said belts, said weft yarnsbeing woven such that they are not interlaced between two adjacent warpyarns at a point where said weft yarns will interfere with lateralcrimping in said warp yarns; b. the vertical distance between the axesof adjacent warp yarns being less than the diameter of said weft yarnsto substantially reduce vertical crimp in said warp yarns; and, c. saidweft yarns having a diameter, measured at a point where said weft yarnscontact adjacent warp yarns, which is greater than the arithmetical meandisplacement between adjacent surfaces of said warp yarns, the lateraldistance between adjacent warp yarns varying substantially continuouslyalong the length of the fabric to accommodate the interlacing of saidweft yarns.
 7. An endless woven forming belt for a papermaking machinecomprising: a. nondeformable synthetic monofilament polyester warp andweft yarns interwoven in a four-harness sateen weave to form said beltwith 62 to 95 weft yarns per inch extending in the lengthwise directionof said belt and warp yarns extending in the widthwise direction of saidbelt, said warp yarns being woven such that they are not interlacedbetween two adjacent weft yarns at a point where said warp yarns willinterfere with lateral crimping in said weft yarns; b. the verticaldistance between the axes of adjacent weft yarns being less than thediameter of said warp yarns to substantially reduce vertical crimp insaid weft yarns; and, c. said warp yarns having a diameter, measured ata point where said warp yarns contact adjacent weft yarns, which isgreater than the arithmetical mean displacement between adjacentsurfaces of said weft yarns, the lateral distance between adjacent weftyarns varying substantially continuously along the length of the fabricto accommodate the interlacing of said warp yarns.
 8. A method ofproducing a forming belt for a papermaking machine with certain of saidyarns extending in the lengthwise direction of said belt and other yarnsextending in the widthwise direction of said belt comprising the stepsof weaving said belt from nondeformable warp and weft yarns with saidwidthwise yarns being woven such that they are not interlaced betweentwo adjacent lengthwise yarns at a point where said widthwise yarns willinterfere with lateral crimping in said lengthwise yarns, and with thevertical distance between the axes of adjacent lengthwise yarns beingless than the diameter of said widthwise yarns to substantially reducevertical crimp in said lengthwise yarns, and with the arithmetical meAndisplacement between adjacent surfaces of said lengthwise yarns beingless than the diameter of said widthwise yarns, measured at a pointwhere said widthwise yarns contact adjacent lengthwise yarns, thelateral distance between adjacent lengthwise yarns varying substantiallycontinuously along the length of the fabric to accommodate theinterlacing of said widthwise yarns.
 9. A method of producing a formingbelt for a papermaking machine having certain of said yarns extending inthe lengthwise direction of said belt and having other of said yarnsextending in the widthwise direction of said belt comprising the stepsof weaving said belt from nondeformable warp and weft yarns with saidwidthwise yarns being woven such that they are not interlaced betweentwo adjacent lengthwise yarns at a point where said widthwise yarns willinterfere with lateral crimping in said lengthwise yarns, and with thevertical distance between the axes of adjacent lengthwise yarns beingless than the diameter of said widthwise yarns to substantially reducevertical crimp in said lengthwise yarns, and reducing the length of thewidthwise yarns by shrinking said yarns until the arithmetical meandisplacement between adjacent surfaces of said lengthwise yarns is lessthan the diameter of said widthwise yarns, measured at a point wheresaid widthwise yarns contact adjacent lengthwise yarns, while holdingsaid lengthwise yarns such that said vertical distance remains less thansaid diameter, to allow the lateral between adjacent lengthwise yarns tovary substantially continuously along the length of the fabric toaccommodate the interlacing of said widthwise yarns.
 10. A method ofproducing a forming belt for a papermaking machine having certain ofsaid yarns extending in the lengthwise direction of said belt and havingother of said yarns extending in the widthwise direction of said beltcomprising the steps of weaving said belt from nondeformable warp andweft yarns with said widthwise yarns being woven such that they are notinterlaced between two adjacent lengthwise yarns at a point where saidwidthwise yarns will interfere with lateral crimping in said lengthwiseyarns, and with the vertical distance between the axes of adjacentlengthwise yarns being less than the diameter of said widthwise yarns tosubstantially reduce vertical crimp in said lengthwise yarns, andreducing the length of the widthwise yarns by subjecting said belt tolengthwise tension and heat until the arithmetical mean displacementbetween adjacent surfaces of said lengthwise yarns is less than thediameter of said widthwise yarns, measured at a point where saidwidthwise yarns contact adjacent lengthwise yarns, while holding saidlengthwise yarns such that said vertical distance remains less than saiddiameter, to allow the lateral distance between adjacent lengthwiseyarns to vary substantially continuously along the length of the fabricto accommodate the interlacing of said widthwise yarns.
 11. A method ofproducing an endless woven forming belt for a papermaking machine withweft yarns extending in the lengthwise direction of said belt and warpyarns extending in the widthwise direction of said belt comprising thesteps of weaving said belt from nondeformable yarns with said warp yarnsbeing woven such that they are not interlaced between two adjacent weftyarns at a point where said warp yarns will interfere with lateralcrimping in said weft yarns, and with the vertical distance between theaxes of adjacent weft yarns being less than the diameter of said warpyarns to substantially reduce vertical crimp in said weft yarns, andwith the arithmetical mean displacement between adjacent surfaces ofsaid weft yarns being less than the diameter of said warp yarns,measured at a point where said warp yarns contact adjacent weft yarns,the lateral distance between adjacent weft yarns varying substantiallycontinuously along the length of the fabric to accommodate theinterlacing of said warp yarns.